首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   48938篇
  免费   5275篇
  国内免费   107篇
耳鼻咽喉   477篇
儿科学   1273篇
妇产科学   1142篇
基础医学   7273篇
口腔科学   1080篇
临床医学   6261篇
内科学   8950篇
皮肤病学   567篇
神经病学   4774篇
特种医学   1925篇
外国民族医学   57篇
外科学   6201篇
综合类   1063篇
一般理论   47篇
预防医学   5550篇
眼科学   1154篇
药学   3817篇
中国医学   24篇
肿瘤学   2685篇
  2021年   712篇
  2020年   443篇
  2019年   701篇
  2018年   813篇
  2017年   600篇
  2016年   662篇
  2015年   696篇
  2014年   1019篇
  2013年   1638篇
  2012年   2161篇
  2011年   2215篇
  2010年   1317篇
  2009年   1128篇
  2008年   2083篇
  2007年   2101篇
  2006年   2146篇
  2005年   2054篇
  2004年   2109篇
  2003年   1859篇
  2002年   1803篇
  2001年   1573篇
  2000年   1682篇
  1999年   1423篇
  1998年   622篇
  1997年   535篇
  1996年   499篇
  1995年   508篇
  1994年   473篇
  1993年   422篇
  1992年   1146篇
  1991年   1173篇
  1990年   1075篇
  1989年   1050篇
  1988年   1048篇
  1987年   928篇
  1986年   920篇
  1985年   878篇
  1984年   735篇
  1983年   615篇
  1982年   430篇
  1981年   390篇
  1980年   382篇
  1979年   714篇
  1978年   539篇
  1977年   456篇
  1976年   440篇
  1975年   403篇
  1974年   464篇
  1973年   467篇
  1972年   410篇
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
61.
62.
Little research has examined the care older people receive in the acute surgical setting. Although pain assessment and management are judged to be a priority in nursing, often pain, in older people, is undermanaged for a variety of reasons. Factors such as stoicism, communication and ageism can shape both the patients’ and nurses’ attitude towards the perception of pain which subsequently affects pain management. Through a review of the literature, this paper aims to: (i) identify how healthcare professionals contribute to the assessment and control of postoperative pain in older people and (ii) explore potential barriers to achieving more advantageous pain control in this group. It is suggested that to improve pain management there is a need to individualize pain assessment for older people and to assist clinicians with enhancing their education and decision‐making abilities in this field. This may best be achieved by supporting a programme of change to develop the skills of staff and encouraging learning through reflective practice. There is however a need for further research in this area.  相似文献   
63.
64.
65.
This study examined the interrater reliability of generalized anxiety disorder (GAD) and major depressive disorder (MDD) diagnoses derived from the Structured Clinical Interview for DSM-III (SCID). Using videotaped interviews, paired raters made independent diagnoses of 75 psychiatric outpatients. The percent agreement of the raters was 82% for MDD and 86% for GAD; the respective kappa values were .72 and .79. The results indicated that the SCID can be employed reliably to differentiate MDD from GAD. The SCID is recommended for further research with these disorders.  相似文献   
66.
Cultured brain cells from rat fetuses of ethanol-treated mothers demonstrated more than 2-fold elevations in choline acetyltransferase (ChAT) activity relative to those of control (saline-exposed) fetal brain cells. When cells from control animals were incubated in vitro for 5 days with 0.1% ethanol, ChAT activity was found to increase more than 4-fold. Brain cells from in utero ethanol-treated animals further exposed to ethanol in vitro for 5 days demonstrated significantly higher ChAT activity compared to cells exposed to ethanol only in vivo. These levels were more than 6 times greater than those of central nervous system cells never exposed to ethanol. Acetylcholinesterase (AChE) activity was significantly elevated (greater than 4-fold) in fetal brain cells when ethanol was present both in vivo and in vitro, but neither treatment alone resulted in any significant changes in AChE. These effects of ethanol on enzymes involved in acetylcholine metabolism may contribute to the different developmental neurologic abnormalities associated with fetal alcohol exposure.  相似文献   
67.
This study was undertaken to determine whether the dose-dependent effect of glucagon on gluconeogenesis parallels its effect on hepatic glycogenolysis in conscious overnight-fasted dogs. Endogenous insulin and glucagon secretion were inhibited by somatostatin (0.8 micrograms X kg-1 X min-1), and intraportal replacement infusions of insulin (213 +/- 28 microU X kg-1 X min-1) and glucagon (0.65 ng X kg-1 X min-1) were given to maintain basal hormone concentrations for 2 h (12 +/- 2 microU/ml and 108 +/- 23 pg/ml, respectively). The glucagon infusion was then increased 2-, 4-, 8-, or 12-fold for 3 h, whereas the rate of insulin infusion was left unchanged. Glucose production (GP) was determined with 3-[3H]glucose, and gluconeogenesis (GNG) was assessed with tracer (U-[14C]alanine conversion to [14C]glucose) and arteriovenous difference (hepatic fractional extraction of alanine, FEA) techniques. Increases in plasma glucagon of 53 +/- 8, 199 +/- 48, 402 +/- 28, and 697 +/- 149 pg/ml resulted in initial (15-30 min) increases in GP of 1.1 +/- 0.4 (N = 4), 4.9 +/- 0.5 (N = 4), 6.5 +/- 0.6 (N = 6), and 7.7 +/- 1.4 (N = 4) mg X kg-1 X min-1, respectively; increases in GNG (approximately 3 h) of 48 +/- 19, 151 +/- 50, 161 +/- 25, and 157 +/- 7%, respectively; and increases in FEA (3 h) of 0.14 +/- 0.07, 0.37 +/- 0.05, 0.42 +/- 0.04, and 0.40 +/- 0.17, respectively. In conclusion, GNG and glycogenolysis were similarly sensitive to stimulation by glucagon in vivo, and the dose-response curves were markedly parallel.  相似文献   
68.
汽车机械学 Bobby是我的汽车修理师,他有一种我喜欢效仿的工作风格。首先他是一位伟大的诊断专家;如果你告诉他汽车出现了什么问题,他会帮你做出鉴别诊断。“运货车是否发动不着了?发动机是否转动?你是否听到了滴滴答答的声音?”问了几个问题后,他便会做出判断。比如我的发动机供不上汽油了,排除了几种可能性后他认为是由燃油泵造成的。  相似文献   
69.
70.
A methodological review is presented of 16 non-therapeutic intervention trials published over the last decade which have randomized intact clusters rather than individuals in treatment groups. Each of the trials was surveyed as to the information supplied on six methodological criteria. Although there is increasing recognition of the methodological issues associated with cluster randomization, many investigators are still not aware of the impact of this design on sample size requirements and analysis considerations. Investigators are urged to publish the cluster-specific event rates observed in their trials as a guide for the planning of future studies.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号